Top loading residential washing machines provide an upwardly open tub into which clothes and detergent may be placed for cleaning. During operation, the tub and its internal spin basket are filled with water, via a solenoid valve, and a central agitator within the tub agitates the clothes and the water to separate the dirt from the fabric (the "agitation cycle"). At the conclusion of the agitation cycle, the water is drained from the tub and the spin basket is spun about its axis to remove the water from the wet clothes by centrifugal force (the "spin cycle").
During the spin cycle, it is important that the tub be covered to prevent injury to the user. For this reason, a hinged lid is provided to cover the opening of the tub during operation of the washing machine. The lid may be connected to an electrical switch (a "lid switch") so that if the lid is opened during the agitation or spin cycles, the washing machine stops.
It is known to position the lid switch on the underside of the top of the washing machine in an area underneath the lid when the lid is closed. A pin extending downward from the lid activates the lid switch, when the lid is closed, to permit operation of the washing machine.
The maximum sensitivity of the lid switch is obtained by positioning the lid switch beneath the front edge of the lid furthest from the lid's hinge. In this position, a pin attached to the lid for activating the lid switch, will have the greatest possible motion when the lid is lifted.
Unfortunately, in this position, the lid switch is particularly vulnerable to water and detergent splash. Further, because the switch is readily apparent, the risk of it being defeated with a pencil or other pointed instrument (so as to operate the washing machine while the lid is open) is increased.
These problems can be avoided somewhat by moving the switch to a position closer to the hinge. However, in this position, the reduced motion of the lid makes it difficult to provide switching during the early stages of opening the lid because of the lack of travel close to the hinge point.